The region in general. Much drier, colder conditions. The
general picture emerging for this region is of a considerable reduction
and southwards retreat of the forest at the LGM, relative to the
interglacial state. Deserts expanded, and even where arboreal vegetation
did predominate, this tended to be of a more open character than during
the Holocene. Lake level evidence agrees with the general picture from
other sources, with many lakes drying up completely around 18,000
radiocarbon years ago (Fang 1991, Winkler & Wang 1993). However,
some lakes (e.g. in NW Tibet) in fact show the opposite trend, towards
moister conditions at the LGM (Winkler & Wang 1993).

The overall picture of aridity in southern Asia fits in with the African
evidence to suggest a general failure of the summer monsoon rains to
penetrate as far north as at present, and a tendency to be less abundant
where they did fall. However, the LGM vegetation of many parts of the
south Asian region remains almost unknown. The greatest certainty on
vegetation character at the LGM is for what are presently the cool moist
temperate latitudes, although information is now becoming available for
other areas too. For those of us from the West, there is the general
problem that we cannot read the considerable literature on the
Quaternary that has been published in Chinese, and must rely on our
Chinese colleagues to translate and interpret this information on our
behalf. My discussion and summary is thus based mainly upon reviews and
tentative LGM summary maps published in English, and upon discussions
with Chinese colleagues.

An LGM vegetation map (18,000 - 15,000 14C yr. BP) for China
has been published (in Chinese) in 1990 by An et al. (Sun
Xiangjun pers. comm., 1992). Wang & Sun (1994) have published an LGM
vegetation map showing a major reduction in forest vegetation and
southwards retreat of climatic zones relative to the present-natural,
although we are inclined to say that considering all the evidence
together, conditions were more arid even than Wang & Sun suggest.

An aridity maximum at 17,000-15,000 14C y.a.?
There are now some signs that conditions around 17,000-15,000 14C years ago were the aridity peak in at least some parts of Eurasia.
In Yunnan Province of the extreme SW of China (Liu 1991), the local warm temperate forest disappeared from the site at around this time.
In eastern and central Turkey, lake levels were lowest shortly after the LGM - 17,000-15,000 4C y.a. (Landmann et al. 1997).
In general, however, conditions in terms of vegetation cover most parts of Eurasia seem to have been similar throughout the interval 18,000-15,000 14C y.a.

Sea level. For cartographic convenience, coastlines are mostly
drawn at the -150 m contour, although this is certainly too low. In
fact, a figure of -125m is suggested for the Indonesian region on the
basis of the latest compilation of evidence (Hantoro et al.,
manuscript in preparation).

Considerable stretches of low lying land were uncovered around the shores
of China, and the Malaysian Peninsula became linked to the islands of
Borneo, Java and Sumatra, and to the Philippines. The islands of Japan
were linked together into a peninsula due to the lower sea level, but probably
remained separated from the Asian mainland by the Korean channel. The
Sea of Japan was almost entirely enclosed as a lake, its only outlet
being the Korean channel.

Ice extent.

The Himalayan region is the only area in the region likely to have had
significant ice cover. It is generally thought that there was not a
large ice sheet over the Himalayan Plateau, but rather a scattering of
glaciers and small ice caps. The extensive evidence of aridity over
south Asia is thought to indicate that there would not have been enough
moisture to support the build-up of such an ice sheet. Studying glacial
tills and other remnants, Han (1991) considers that he and his
colleagues have now found the necessary evidence of continuous ice cover
during the early-to-mid Quaternary glaciations, but for the last glacial
maximum he regards the glaciers as having been small in scale and mainly
confined to small valley glaciers, due to aridity. Permafrost desert
conditions appear to have existed in the unglaciated Himalayan regions
(Thompson pers. comm.). This general scenario of limited glaciation is
acknowledged in the CLIMAP (1981) map of the LGM, which shows only
10-20% ice cover in this region.

However, Kuhle (1991) seems confident that he has assembled the
necessary evidence for a very extensive ice sheet covering all of the
Tibetan Plateau (from the Himalayas north to Kun-Lun Shan) during the
last glacial. The lower equilibrium line of the ice sheet would have
been around 4000m a.s.l. (1100-1600m lower than today), so all of the
land above this altitude would have been ice-covered. This putative ice
cap may have reached 2.7 km thickness at its centre (Kuhle 1991). Such
an ice cap would require considerable precipitation over the Plateau
during the LGM period, and seem to stand in surprising contradiction to
the LGM aridity seen elsewhere in southern Asia.

In the map reconstruction here, the more widely accepted view of Han
(1991) is assumed; in any case there would have been effectively no
vegetation in the higher plateau region for the LGM. For the Himalayan
region in general, we suggest a topographic mosaic of 70% polar desert,
and 30% dry montane tundra.

Northern China (north of about 30N).

Much colder, much drier. The general indications are of much
colder, more arid conditions than at present. Lake level evidence
almost everywhere indicates dry conditions, with complete drying-up of
many lakes (Winkler & Wang 1993). On the basis of diverse
palaeoevidence (summarised below), Petit-Maire et al. (1994)
present a rough summary sketch diagram suggesting that the summer
monsoon limit was shifted some 700 km to the south-east in Northern
China; a shift of this order would bring the semi-desert steppe
climates of eastern Mongolia down into central China.

Eastward expansion of the central Asian desert belt The
widespread distribution of loess in Northern China (and extending
eastwards to Korea) indicates more extensive central Asian desert
conditions at around the LGM (Pye & Zhou 1989). Although most loess
sections have not been radiocarbon dated - due to the paucity of organic
matter - correlation with marine isotope records indicates that the
loess was deposited under glacial conditions, alternating with stable
soil-forming conditions during warmer, moister interglacials. Magnetic
susceptibility of loess sequences, tentatively correlated with ice-core
climate evidence, suggests a much drier climate than now in the Linxia
area on the western Yellow River loess plateau uplands (about 103 E, 36
N). Li et al. (1995) suggest that around 18-22,000 ('real' rather
than 14C?) years ago there was a much drier climate than at
present, about 100mm as opposed the present annual rainfall of 350mm.
Mean temperatures seem to have been about 6 or 7°C lower than at
present. Palynomorphs recovered from loess indicate that during each
glacial interval the vegetation was much more open than today's, with
the dominance of pollen of herbs and grasses in many loess horizons, in
contrast to the arboreal types found during the present interglacial
conditions. In a recent analysis of the isotope ratios of organic matter
extracted from a loess section (109E, 37N) in central north China,
Frakes & Jianzhong (1994) found that C4 plants were considerably
more abundant than at present at the LGM, although C3 plants remained
dominant both at the LGM (55-60%) and throughout the Holocene (>80%).
In fact, over almost all of northern China at the LGM, there appears to
have been 'severe desert with almost no pollen influx' (Sun X., pers.
comm., Jan 1992). Cold, arid conditions are also indicated by molluscan
palaeoecology (Frakes & Jianzhong 1994).

Although the degree of soil development and organic matter content of
the loesses in north-central and north-eastern China tends to be
somewhat higher than for the European loesses (data in; Li et al.
1995), the lack of evidence for soil development (e.g. high
CaCO3 content) in the loess which was deposited at around the
LGM further supports the view that the whole area was cold and arid with
low biological activity and a sparse herbaceous vegetation cover.
Presumably the areas to the west, from where the loess was derived and
blown by the winds, were even more arid. To a great extent, the source
of the loess dust seems to have been the aridified uplands of the
Tibetan Plateau (Li et al. 1995). Dust influx to the north
Pacific from China reaches a strong peak at the LGM, possibly reflecting
greater aridity over Asia at that time, although wind strength may have
been greater and thus better able to carry the dust (Hovan et al.
1989). However, some other records indicate a dust peak in the Pacific
during the Holocene and not the LGM (Street-Perrott pers. comm. 1995).

Low lake levels over northern China generally support the view that
conditions were more arid at the LGM than at present. Yet although the
level of Dalai Lake (112E, 40N) was much lower at the LGM than during
most of the Holocene, it was apparently higher than it is today (An
et al. 1993). Pollen recovered from surfaces correlated as being
approximately contemporaneous with the LGM, in the same area in
North-western China, close to Mongolia (112E, 40N), shows that
xerophytic plants (especially Artemisia and Chenopodiaceae) were
virtually the only ones present (An et al. 1993), in a region
that presently has a much denser grassy steppe cover. However, the
proximity of this area to the present Ordos Desert perhaps suggests that
in fact the spatial shift in climate might not have needed to be very
large (editors' observation).

Arid steppe in the north-east. For the north China plain and NE
China ('Manchuria'), a cold and very sparse steppe-tundra dominated by
Artemisia with grasses and chenopods was the predominant
vegetation (Liu 1986, Wang & Sun 1994). Trees appear to have been
absent during the period of the LGM itself. The aridity itself seems
likely to have prevented pollen deposition in many sites at the LGM, but
radiocarbon-dated pollen diagrams from Beizuanaguan (109 E, 34N) and
also near Beijing indicate this sparse Artemisia vegetation.

Mammoths (Mammuthus) also seem to have been absent from the
Yellow River basin and the continental shelf area at around the LGM,
possibly due to aridity leading to very sparse vegetation, although they
had been were abundantly present in the area both before and after the
LGM (An et al. 1991). Arid as well as windy conditions in
north-east China are further indicated by sand dunes, detected by
seismic profiling on the bed of the southern Yellow Sea (around 35N).
This area is thought to have been land at the LGM, and a last glacial
age is indicated by radiocarbon dates ranging between 10,000 and 20,000
years ago in the muddy deposits that overlie these dunes (Wang & Sun
1994). Further evidence of aridity in north-eastern China is provided by
the occurrence of radiocarbon-dated LGM loess deposits (already referred
to in passing, above) across the Bohai Bay (around 120E and 40N) and
even southwards of the Yangtze River (25-30N) (Li & Zhou 1993).Dust
(though not loess) deposits also occur on islands in the east China Sea
(Wang & Sun 1994). Whilst loess deposition itself is thought to
require the presence of some vegetation, it emphasises the arid nature
of most of northern China. The only partially weathered nature of the
LGM loess-soils also suggests that even where the loess was deposited
and stabilised, it was in a semi-arid environment (Li & Zhou 1993).

Treelines. Treelines in mountainous areas in both northern and
southern China were about 1,700m lower than at present (An et al.
1991). For example, An et al. (1991) report treeline depressions
of about 1,200m in Guizhou.

East-central China (around 30-35 Deg.N).Deserts on the continental
shelf, but parklands also? An et al. (1993) report that
active dunes and desert or semi-desert conditions are widespread in the
middle-lower Yangtze River basin at around 18,000 14C years
ago. As mentioned above, loess deposition was also occurring in the
Yangtze area at the LGM. However, there also seems to have been at least
some parkland and/or boreal woodland vegetation in the lower Yangtze
area, with Chen & Olson (1990) reporting that in east China there
are LGM pollen assemblages with high percentages of Pinus, Abies,
Picea, indicating a mean annual temperature depression of 9 -
13.5°C.

Taiwan; steppe in some areas, forest in others. In Taiwan, which
would have been connected to the Chinese mainland during the LGM, pollen
cores on the western side of the island - presently covered by moist
temperate evergreen forest - indicate dry steppe vegetation (87%
herbaceous, with 36% Artemisia), although trees (especially
Pinus and other Pinaceae) were present to some extent, perhaps in
a wooded steppe (Lin & Liew 1986). Similarly, a new pollen record
from a peat bog in the uplands (650m a.s.l.) of central Taiwan shows
that at the LGM the present moist Castaneopsis forest was absent
and its place taken by a herb-dominated assemblage (about 66% herbaceous
pollen, consisting of grasses and sedges with Umbelliferae). The main
tree present was a drought-tolerant species of Alnus (Liew et
al. 1995, Liew et al. 1998). On what are presently the highest rainfall areas in the
uplands of the north-east of the island, further pollen evidence
indicates that at least some forest vegetation persisted through the
LGM, but under rather cooler conditions than today, with Quercus
instead of the more warmth-demanding Castaneopsis.

An overview of Southern China; woodland absent from areas with present precipitation below 1600mm?.
Liew et al. note that even in places in eastern China and Taiwan where tree cover was predominant at the LGM, from the presence of abundant grass and open-ground pollen and spore types,
it seems to have been fairly open (perhaps more a 'woodland') in those areas. Liew et al. show a present-day annual precipitation map of southern China (p.93).
It is interesting to note that two pollen sites which were apparently steppe at the LGM (Pearl River at about 23 deg.N, and Ningbo Plain at 26 Deg.N) have present precipitation
above 1400 mm, but evidence of long-distant transport of tree pollen from uplands receiving about 1600mm or more. If we extrapolate this relationship across southern China-Taiwan
for the LGM, with all areas with less than 1600mm present rainfall being steppe, and those above 1600mm being forest or open woodland, most of
southern China would be steppe, with areas of wooded vegetation in the scattered uplands covering about a third of the region. Even this may be a conservative estimate in favour of forest
cover; mid and low altitude sites on Taiwan with annual rainfall above 2000mm also seem to have lost their forest cover
at the LGM.

Open pine forests in the west. In west-central China, on the
upland plateau region of the upper Yangtze (around 25N, 110 deg.E), a pollen core
indicates pine (Pinus) forest at around the LGM. This was
probably a more-or-less open forest or woodland, judging from the low
pollen influx values (Sun Xiangjun 1990). This seems to fit with the pattern
hypothesized above; that a rather open wooded vegetation survived in areas with greater than 1600mm
annual precipitation.

South China.

Drier, with savanna development in the present rainforest zone in the
south-east. Chen and Olson (1990) suggest that in south and
south-east China generally, there were relatively insignificant
differences in climate from the present at the LGM. Liu (1991) mentions
that although there is little or no sign of temperature depression
during glacials in southernmost China.

However, Wang & Sun (1994)
refer to the subtropical rainforest having disappeared from southern China and
replaced by mixed conifer and evergreen broad-leaved forest, although
they do not cite any specific sources. In places, conditions may have
been more arid than this.
Reviewing the pollen evidence at several pollen sites scattered through SE China (e.g. Min River Delta 26 deg.N, Pearl River Delta 23 deg.N),
Liew et al. (1998) conclude that grasslands predominated in lowland areas,
with cool temperate forest and open woodlands in upland areas. On the Leizhou Peninsula in southernmost
China (20 deg.N), which presently has a very moist, warm climate and paratropical rainforest, a relatively northerly warm temperate pine/oak forest was present and
with signs of more arid conditions (pollen of grasses and open-ground ferns among the trees, and sedimentary evidence of drier conditions).
Winkler & Wang (1993) already suggest a belt of 'forest and grassland' across southern China at the LGM, but from
the evidence of Liew et al. it seems necessary to conclude that the LGM vegetation map of Winkler & Wang (1993) shows too much forest in south-eastern China/Taiwan.
Wang et al. (1977;
published in Chinese and cited by Winkler & Wang 1993) obtained a
pollen-bearing core from Beibu Bay (22N, 109E) showing undated wet-dry
cycles in vegetation during the Quaternary that are suggested as
paralleling the cold-warm cycles found elsewhere. During the dry
intervals, pollen from savanna plants such as grasses and
Artemisia was abundant, in contrast the predominance of
tropical/subtropical trees during moist intervals. It may be appropriate
to correlate these phases of savanna expansion with the steppic
expansion seen on the adjacent shelf area west of Taiwan, indicating a
general opening up of the forest vegetation, but such a conclusion is
tentative. Cores from the South China Sea (around 20N) showing increased
sediment deposition rates have been taken to indicate drier conditions
at the LGM, but Wang & Sun suggest that this conclusion might not be
justified and simply due to further extension of rivers out across the
continental shelf. In the maps here, an opening up of forest vegetation
in south China is tentatively shown, considering the pattern of aridity
seen in Taiwan and other areas further to the north, and also to the
south in Indo-China.

Survival of warm temperate forests in the south-west. In the
mountainous areas of Northern Yunnan Province, there are indications of
snowline lowering, indicating a 4-5°C depression in temperature.
Slightly moister-than-present LGM conditions are indicated by the levels
of the two montane lakes Dianai Lake and West Lake (An et al.
1993) in Yunnan Province in the extreme south-west.

From a pollen sequence dated to just before the LGM (finishing at 20,000
14C yr. B.P.) at Xishuang-banna in the present subtropical
rainforest zone in the uplands of Yunnan Province of the extreme SW of
China, Liu (1991) suggests that the LGM climate was nearly warm as at
present, but with much higher precipitation in winter (as indicated by
the presence of the subalpine tree Dacrydium). The driest period
at this particular site, in which pine-oak scrubland with abundant herbs
replaced the forest apparently due to a reduction in winter rainfall, is
suggested as occurring after 18,000 years ago rather than within
the interval 20-18,000 years ago. Hence
the map reconstruction here conservatively suggests a belt of moist
evergreen warm temperate forest persisting, somewhat further south than
at present due to temperature depression.

A forthcoming overview of vegetation distribution in China from the BIOME 6000 group.

A summary paper on LGM environments across China has been submitted to J. Biogeog. by 28 regional authors (Ge Yu et al.) for the BIOME 6000 vegetation
reconstruction project. Its findings seem closely in agreement with picture outlined above.

Japan.Open woodland. For Japan, the abundant plant fossil
evidence for the LGM (more than 52 pollen sites and 34 macrofossil
sites; Ooi et al. 1990) from both onland and offshore cores shows
a general southwards shift of the vegetation zones under LGM conditions
(Reynolds & Kanser 1990). Permanent ice seems to have covered the
uplands of what is now the northernmost island (Hokkaido), with a belt
of tundra and open boreal woodland (with extensive grassy openings) dominated by
Larch (Larix) and Spruce (Picea) (Igarishi 1996).

The open-ness of the LGM vegetation
throughout Japan seems to have been added to by the fall of an extensive
volcanic ash deposit just before the LGM (Ooi et al. 1990).
Radiocarbon and ash-dated pollen-bearing sites near Lake Biwa in
east-central Japan (Ooi & Sei-ichiro 1989) and at several other
localities across the centre of Japan (work published in Japanese, cited
by Ooi & Sei-ichiro 1989) indicates that the lowland vegetation at
the LGM was Cyperaceae-rich grassland with sparse scattered stands of
Alnus, Fraxinus and Salix. Forests of a rather open
character with Quercus and Pinus seem to have been
widespread in the mid-altitude uplands. Open boreal-type woodland
(consisting mainly of Pinus, with Abies and Betula)
covered much of Japan's uplands (Heusser 1990), from about the middle of
the main island to the south of the linked chain of islands.
Artemisia was often present, indicating dryness (Ooi et
al. 1990).

Warmer temperate elements of the flora (e.g.
Cryptomeria) persisted only locally as minor components in
lowlands towards the southern part of Japan, which seems to have had a dry cool-temperate
climate with open vegetation and scattered woodland on the uplands (Ooi
1992). Mean annual temperature in SW Japan seems to have been about 7-9 Deg.C lower and precipitation was
probably less than 1/3 of present values (Yasuda 1990).

Indo-China and Malesia. There is little information from
Indo-China and Malaysia in general. The records which do exist are often
ambiguously dated.

Drier conditions in Thailand. Morley & Flenley (1983) refer
to undated pollen evidence for pine forest occurring in the present
rainforest areas of Thailand and Malaysia, which they suggest as
possibly being of LGM age. In the lower Mun river basin, north eastern
Thailand, there is loosely dated geomorphological evidence of widespread
desiccation associated with aeolian activity and an increase in ground
water salinity after 20,000 years ago (Loeffler et al. 1984). The
aeolian activity does not seem to have been sufficient to form true dune
systems, but riverine sands and silts were blown as sand sheets and
loess layers onto the slopes and uplands surrounding the Mun River.
Loeffler et al. note that savanna species occur in pollen-bearing
cores further south, but they do not state how much further south or
what sources they are referring to.

It is interesting also to note that a deep sea core (Core 35-5) taken at
7N, 112E shows a much higher terrigenous sedimentation rate during the
LGM (correlated by oxygen isotopes) than the Holocene. This has been
ascribed to aridity and sparser vegetation cover on the tropical land
area to the west (southern Indo-China and Malaysia) allowing greater
riverine erosion (Broecker et al. 1988). Wang & Sun (1994)
suggest that in fact this increase in sedimentation might have been due
to the extension of land area with the sea level fall (bringing the
river mouths out closer to the core site), rather than an increase in
aridity.

Cooler but moist in uplands of Sumatra and Java. In Sumatra and
west Java, two lake sediment records in the mid-altitudes (about
1300-1500 m a.s.l.) indicate drier climates, but there are no
indications in the pollen records from these sites of any drying
of climate, with everwet indicators persisting through the LGM (Stuijts
et al. 1988). If the lake sediment evidence is to be believed, it
may indicate a regional decrease in rainfall, that could have affected
what are presently the more seasonally dry areas rather more severely.
However, it is a matter of guesswork as to how much loss of rainforest
there would have been. From these palynological records, there appears
to have been a cooler-than-present climate, by at least 1.8°C and
perhaps as much as 7°C (which would give a vegetation zone lowering
of about 1200m).

Loss of forest from West Java. A recently obtained (U/Th and
14C dated) pollen core in the intramontane Bandung Basin in
West Java (665m a.s.l., 1700mm precip.) indicates that the present
freshwater swamp forests were absent during the LGM and were instead
replaced by a vegetation similar to the scrubland-grassland of
southernmost New Guinea (S. van der Kaars & R. Dam. MS submitted for
publication 1994). By their reckoning, this vegetation change would have
required about a 30% reduction in annual rainfall. A lowering of the
mean annual temperature at the site (presently 23.3°C) by about
4-7°C is also indicated.

This site is of interest as the first well-dated lowland rainforest core
in the region. It suggests that there was indeed a net loss of lowland
rainforests in south-east Asia, and that the adjacent montane pollen
records do not acknowledge this drying; possibly because their rainfall
totals are too large to register effects from any similar diminution in
rainfall that did occur in the mountains. In fact, if such significant
drying could occur in an area relatively close to the moisture source of
the sea, it suggests that there would have been an even more arid
climate and sparser vegetation over most of the exposed central
Sundaland mass.

Loss of forest from western Borneo? In what is presently an
ever-wet rainforest climate (3200-5000mm annual rainfall) area in
lowland western Borneo (Kalimantan), there is evidence of savanna
development, with high frequencies of grass pollen at some stage
during the late Quaternary (Caratini & Tissot 1988). Thomas &
Thorp (1992) note from the available radiocarbon dates that during the
earlier Lower Pleniglacial (approx. 60,000 years ago) glacial period
large amounts of angular sediment (e.g. the white sands) were deposited
in coastal Kalimantan, apparently transported by braided streams with
occasional flash-floods, probably in a savanna environment. Whether this
earlier glacial phase resembled the LGM in this area is a moot point,
although in many parts of the world where there are long records it is
closely similar to the last glacial. A second phase of alluvial
sedimentation seems to correspond to late glacial age; in these deposits
there are two near-basal dates of 10,500 14C yr. B.P. (see
Thomas 1994 p.233). This continuing slope wash into the lowermost
Holocene may reflect the effects of continuing lower sea level in
preventing moist air moving inland, or perhaps a lag in recolonisation
of surfaces by closed forest vegetation.

Rainforest surviving in northern Borneo. In the presently
ever-wet rainforest region of Sarawak and Sabah (northern Borneo), there
is apparently palaeozoological evidence for the persistence of
rainforest through the LGM. At the Niah, Tingkayu and Baturong cave
sites, T. Harrison & B. Harrison are reported to have found that
humans during the LGM interval were hunting wild dog, tapir and Javan
rhino, all of which are characteristic rainforest species (cited without
references in Edwards 1994). However, more recent paleozoological work on a cave suggests
that the LGM in northern Borneo was a period of open non-forested or woodland conditions (unpublished work in progress). If so,
my map may show too much forest in Borneo for the LGM.

The vegetation of central Sundaland; mangrove swamps? Bellwood
(1990) refers to the work of Biswas in 1973, describing the results of
core analyses from the bed of the South China Sea east of the Malayan
Peninsula. Biswas suggested that during glacial periods there were
brackish lagoons and bays at the centre of the Sundaland basin, bordered
by widespread mangrove swamps and forests. However, the only published
radiocarbon dates that have been obtained for peats from Sundaland fall
within the age ranges >30,000 years ago and <12,000 years ago, so
the mangrove swamps could well have been from these age bands. Biswas
had only one radiocarbon date to base his case upon, and this was a peat
sample 11,100 years in age and thus more nearly Interglacial than
Glacial in age (though possibly indicating Younger Dryas-age vegetation;
a potential analogy for deducing LGM conditions). As Morley (pers.
comm., July 1994) suggests, this peat could just as well have come from
a narrow fringe of strandline vegetation as an extensive mangrove swamp
of the sort that Biswas proposes.

There is apparently no other palaeo-evidence as to the nature of the
vegetation in the large central area of shelf exposed by low sea levels
during the LGM. Thomas & Thorp (1992) note Walker's speculation that
the rapid oscillations in sea level (1.9-1.5m per century) at around the
LGM would have meant that there would have given insufficient time for
rainforest colonisation between these sea level oscillations and
mangrove phases, especially due to the delays in colonisation caused by
brackish soils left behind as the sea retreated.

Geomorphological evidence for aridity in the south of the Malay
Peninsula. Fluvial braided-stream deposits which occur in the
southern Malay Peninsula and Singapore are generally regarded as having
been deposited during typical 'glacial' phases, and geologists currently
describe these deposits as 'semi-arid' (Morley pers. comm. 1990).
Similar deposits around Palembang are also apparently glacial in age
(Morley pers. comm. 1992, Thomas & Thorp 1992). Landforms in
granitic terrain are described by Banka and Billington (cited by Morley
pers. comm.) as being formed under seasonal climates that they
hypothesise may have been glacial in age. Thomas & Thorp emphasise
that one might expect that if there was a large area of shelf exposed in
SE Asia, this central area would tend to receive less rainfall from the
sea, and an initial loss of forest would be amplified due to a reduction
in transpirational recycling of water across the land surface.

Biogeographical evidence for dry forest expansion. Extension of
the relatively dry monsoon forest right across the region during
glacials is perhaps also supported by the present-day disjunct
distribution of plant species (e.g. the neem, a typical monsoon forest
tree) which occur in central Malesian areas such as Java (Whitmore
1983). This biogeographical evidence is relevant in the sense that it
might be regarded as indicating the coincidence of drier conditions and
lower sea levels in the past.

Highlands were cooler but only slightly drier at LGM. However,
Barmawidjaja et al. 1993 note (as mentioned briefly above) that
the data in previously published studies from highlands of
Sumatra, Java and New Guinea all suggest cooler temperatures
(2-3°C) but not drier conditions in this region at the LGM.
However, it is worth noting that coarser sediments from about 18,000
14C years ago onwards during the glacial may indicate
somewhat drier conditions at these sites (Thomas & Thorp 1992). Van
der Kaars (pers. comm.) suggests that in the Malay Peninsula's upland
areas, precipitation did not go far below 2000mm.

Marine sediments from the Sulu Sea, south-west of the Phillipines, have
been taken as suggesting no decrease in rainfall at that time (Lindsey
& Thunell 1990). However, on the basis of palynological evidence
from cores taken in the northern Molucca Sea (Indonesia), Barmawindjaja
et al. (1993) suggest that in fact conditions were somewhat more
arid than today at the LGM. The actual degree of aridity that they
envisage is not clear from their paper, but they do find a major
decrease in rainforest elements and fern pollen at the LGM, perhaps
partly due to decreased stream runoff as well as actual vegetation
change. But instead of increased aridity, a lowering of the altitudinal
vegetation zones on the nearby islands from which the pollen is derived
may have been partly or largely responsible for this change (W.A. Van
der Kaars pers. comm 1993); there is a large increase in pollen from
submontane Fagaceae.

Map interpretation. R. Morley (pers. comm., March 1992) has
kindly drawn up for us a preliminary sketch map for Malaysia/Indonesia
at around 18,000 years ago, showing rainforest largely confined to
peripheral areas of Sundaland, in north and eastern Borneo, and western
Sumatra. He suggests 'monsoon and deciduous forests' and savannas over
large areas, and these we have interpreted as roughly equivalent to my
woodland/monsoon forest category in terms of structure. He tells us that
map he gives has been based on a mixture of pollen evidence, loosely
dated sedimentological evidence and undated dry-climate landforms.

Considering the evidence of drier conditions from around the exposed
landmass of Sundaland, and the fact that the central region would have
been relatively cut off from rainfall (as GCM predictions also
consistently tend to indicate), we suggest a dry forest and savanna belt
along the central region.

India, Pakistan and Bangladesh. India seems to have been
generally much drier and more sparsely vegetated at the LGM than it
would naturally be at present. Evidence from pollen off the southern
coasts of India suggests that savanna and open vegetation were more
widespread than at any time during the Holocene (Erdelen & Preu
1990).

North-western India; desert conditions in Rajasthan. In the north-west, Sarnthein (1982) maps sand-dunes
as indicating fairly widespread desert conditions at around the LGM in
north-west India. Goudie (1983) likewise maps extensive desert
conditions indicated by active sand dunes in north-west India for the
LGM. These reconstructions are based, for example, on the dated evidence
of Bryson & Swain (1981), who find that what is now a lake in
Rajasthan (NW India) was a dune field before the start of the Holocene.
Other lake level evidence in northern India (lakes Didvara and
Lunkaransar) shows a similar picture of LGM aridity (Singh et al.
1974, Agrawal 1988).

Probable aridity in Kashmir?. In nearby Kashmir Province (in extreme north-western India),
palaeosol development and a C3-dominated grass flora was thought to have been
present at about 18,000 years ago, following an aridity maximum just
before this time (Agrawal 1988). In the lowlands of Kashmir Valley,
palaeosoils have been dated to around 18,000 years ago. Analysis of
their carbon shows it was derived from C3 vegetation, indicating cool,
moist conditions (in contrast with earlier palaeosol phases which were
C4 dominated). Likewise, a bog at 3000m in Kashmir was thought to show fairly moist
LGM conditions, with the localised presence of some temperate tree taxa
(Agrawal et al. 1990). However, that there is currently
some dispute about the dating of the moist phase, with it possibly in
fact being older than 24,000 years ago and with LGM aridity.
Street-Perrott (pers. comm. 1995) notes that two other more rigorously dated and recently obtained recent
pollen diagrams suggest LGM aridity in this area.

Evidence of aridity off the west coast of India. Salinity in the
northern Arabian Sea appears to have been higher than today, indicating
decreased input from rivers. On the basis of two offshore cores at 10
and 15N, Van Campo (1986) suggests that reduced rainfall and reduced
runoff of rivers from the western Ghats (the hills running along the
west side of India) was responsible for a great reduction in mangrove
vegetation and an increase in herbaceous pollen (e.g. Gramineae,
Chenopodiaceae). The LGM aridity along western India generally seems to
have been severe; van Campo (1986) remarks that the LGM conditions on
the eastern side of the Arabian Sea would have been about as arid as
those on the western side.

North-central India and Bangladesh; more arid than present. In
north-central India, there is radiocarbon-dated sedimentological
evidence that two rivers had much more sparsely vegetated catchment
areas than at present, around the time of the LGM (Williams & Clarke
1984). These two rivers, the Son and Belan, originate at about 23N in
the low Kaimar range of hills, and so presumably reflect the general
shift in the environment in Northern India.

So far, there seems to be no direct evidence on the vegetation of
Bangladesh at around the LGM. In the northern Bay of Bengal, planktonic
evidence indicates that sea surface salinity was much higher than today,
resulting from decreased freshwater input from the
Ganges-Brahmaputra-Irrawady river system. This provides a further
indication of a reduction in summer monsoon rainfall (Cullen 1991).

Although sediments of last glacial age have not been
analysed from a palaeoenvironmental viewpoint, there are poorly dated
mid-to-upper Quaternary palaeosol sequences from NW Bangladesh (24 deg.N, 88 deg.E)
with carbon isotopic values and intermittant carbonate concretion phases that show strong wet-dry cycles (Alam et al. 1997).
The wetter parts of the climate cycles suggest high annual rainfall (similar to the present 1244mm) and forest vegetation. The
drier phases suggest less than 750mm annual rainfall, and dry C4-grassland and scrub vegetation. The drier parts of
these cycles might correspond to the general glacial-interglacial pattern of aridity oscillations
seen across southern Asia, but interglacial arid phases cannot be ruled out.

On the basis of the marine cores and sedimentological evidence showing a decrease in river runoff,
and the general pattern of south Asian aridity,
we suggest that the present monsoonal forest belt would have been
largely replaced by scrub or grasslands at about the LGM-late glacial.

Southern India. In south-western India, a high altitude site in
the Nilgri Hills (>2000m above sea level) at the LGM is marked by a
strong dominance by C4 plants, and an absence of woody vegetation, as
indicated by the isotope composition of peats (Sukumar et al.
1993). This is interpreted as indicating more arid than the present
conditions, which have C3 grassland interspersed with stunted montane
evergreen forest (a direct CO2 effect might also be involved,
since the plants themselves would presumably have been rooted in
year-round moist substrate conditions in order for the peat to have been
preserved). By extrapolation, one can surmise that at lower altitudes of
the Western Ghats there would likewise have been drier-than-present
conditions and a retreat of forest.

With lower sea level, Sri Lanka would have been connected to mainland
India via the Palk Strait. Erdelen & Preu (1990) mention work by
Moore on mammalian biogeography, suggesting that Sri Lankan rainforest
squirrels dispersed across continuous rainforest on the Palk Strait
during low sea level glacial phases. However, Erdelen & Preu take a
contrasting view that in fact the last glacial maximum was more arid
than present, citing presently unobtainable work by Deraniyagala
published in 1981, on animal fossils and archaeological sites showing
that lowland rainforests on Sri Lanka were contracted and restricted to
the periphery of the Central Hills (they suggest however that conditions
around 30,000 years ago might have been moist enough for rainforest on
the exposed shelf). Erdelen & Preu thus instead suggest that the
exposed Palk Strait would have been covered in dry forest or
savanna-like vegetation, and although they refer to some 'poorly dated'
pollen data it is not clear from their wording whether it is actually
from the Palk Strait itself.

The general picture of greater aridity is backed-up by various
oceanographic studies showing evidence of a weaker summer monsoon wind
flow over the Indian Ocean (e.g. Rostek et al. 1993). This
reduction in the northwards air flow would be expected to have given
less rainfall over the region as a whole.

Conclusion; A fairly arid India at the LGM. From all this
scattered evidence, it does seem overwhelmingly likely that all or most
of India was considerably drier than present at the LGM. However, the
general nature of vegetation at the LGM remains highly speculative, as
there is not enough direct evidence to show precisely what degree of
aridity occurred over most of the land surface.

Pakistan; lack of evidence. There seems to be no evidence from
Pakistan and Afghanistan, although it is reasonable to suppose that the
regional pattern of greater aridity would have extended across the
southern part of this area. However, moist (winter rainfall) conditions
may have prevailed in the north, as in Iran to the west.

Other parts of the Middle East. There is relatively little evidence from the area
between western Iran and western India. A pollen site, and the lake Zeribar site, from the
Zagros mountains of western Iran shows drier and cooler than present
conditions at around the LGM, with a semi-desert Artemisia and
chenopod steppe predominating (Bottema & van Zeist 1988). N. Roberts
(Loughborough University, pers. comm.) suggests that such arid steppe
would have predominated over the whole area, in the place of the
woodland that is the present-potential vegetation. The central
Iranian Plateau seems to have been more arid than present with, extensive dune fields were active on the
Plateau at around the same time; due to a combination of greater aridity and stronger wind speeds
(Krinsley 1966). Thomas et al. (1997) find further evidence of cooler and drier conditions on the central Iranian Plateau around the LGM (with the driest phase ending around 17,000 y.a., according to optical dating) in the form
of frost-shattered and windblown sediments.

8,000 14C years ago (early Holocene). .

Sea Level Given that relative sea level was still lower than
present in some parts of the world, partly due to the remaining parts of
the Laurentide ice sheet, it is likely that coastline in many areas of
southern Asia extended slightly further seawards than at present.
However no maps seem to be available for this time slice at 8,000
14C y.a., so present-day coastlines are illustrated here. In
the Yellow River delta of China, in contrast, relative sea level seems
to have been higher than today (possibly due to a legacy of reduced
sediment build-up during the preceding glacial phase). Here, the sea
apparently came in 80-100 km further inland than now, between 8,000 and
5,000 years ago (Yang & Wang 1990).

Moister and warmer than present, across the monsoon belt. At
8,000 years ago, the south Asian region in general seems to have been
strikingly moister and slightly warmer than at present. The greater
moistness fits in with a general pattern extending across into northern
Africa, reflecting greater summer monsoon rainfall at that time. Lake
level evidence over all of China and Mongolia shows conditions moister
than present between around 9,500 and 5,000 years ago (e.g. reviewed by
Winkler & Wang 1993, Petit-Maire et al. 1994). However, Gasse
& Van Campo (1994) find evidence from lakes in Tibet and Rajasthan
of a major dry phase somewhere between around 8,000 and 7,000 years ago.
This probably extended across much of the monsoon belt, as they note
that it also shows up in lake levels across west Africa. However, my
reconstructions here assume the 'background' moister state occurred at
the 8,000 years ago time slice itself.

China.Warmer and moister. For China, vegetation maps
published by An et al. (1990) and Winkler & Wang (1993) are
based on fossil and sedimentological evidence that at 8,000 years ago
conditions were significantly warmer and moister than present. A
northwards shift of the forest belts is shown; this was the result of a
sudden rise in high forest tree species at the expense of Betula
just before 8,000 years ago (Winkler & Wang 1995) (perhaps
reflecting either climate warming or ongoing ecological succession) and
also a westward expansion of forest and grassland hundreds of kilometres
towards the now-arid central Asian interior.

In the Loess-Plateau area of north-central China, the vegetation seems
to have been existing under moister conditions than at present. The
proportion of drought-tolerant C4 plants in the vegetation seems to have
reached its lowest point during the early-to-mid Holocene, before
increasing slightly towards the present (Frakes & Jianzhong 1994).
At the Linxia site in the western part of the Loess Plateau, magnetic
susceptibility suggests a rainfall of around 460mm compared to the
present 350mm, between about 8,000 and 3,000 years ago, with
temperatures about 2°C warmer than at present (Li et al.
1995). Other recent magnetic susceptibility work suggests that in the drier western part of the Loess Plateau,
annual rainfall was 60-100% higher than present at around 9,000-6,000 14C y.a., but
towards the east of the Loess Plateau it has remained about the same since 8,000 14C y.a.

Many forest tree species extended their ranges further north and west
than at present between 8,000 and 5,000 years ago, indicating
precipitation about 100mm higher than today in many areas of China, and
temperatures were perhaps 2-4°C warmer (An et al. 1990,
Winkler & Wang 1993). For example, conditions according to
palynological evidence seem to have been around 3-4°C higher than
now in Beijing and 2-4°C higher in the lower Yangtze river area
(Sun & Chen 1991), reflected in terms of the northward movement of
tree taxa. The deciduous forest of north-eastern China seems to have
been expanded a couple of hundred kilometres northwards into the Russian
far east (Velichko 1991). In this north-eastern area, Betula and
Pinus pollen were at lower percentages than at present, their
place being taken by other, warmer-climate broad-leaved species.

Along the east China coast down to around Shanghai, it seems that the
sea came in about 100km inland relative to the present coastline (Tong
& Shao 1991).

The maps shown here are based on the various sources of evidence
discussed by An et al., including pollen cores from lakes.
Winkler & Wang (1993, p.245) also present a map for the early-to-mid
Holocene moist phase with an extension of forest vegetation hundreds of
kilometres westwards into the Inner Mongolian and Tibetan steppe
zone.

Central Asian desert belt.

Significantly moister with steppe vegetation.

Petit-Maire et al. (1994) suggest on the basis of the combined
palaeoevidence that the summer monsoon extended a further 300 km or so
north-westwards into inner Mongolia, relative to its present limits.
This generally moister-than-present phase began around 9,000 years ago
and ended around 5,000 years ago.

Winkler & Wang (1993) discuss the ambiguous (poorly dated) evidence
of pollen and buried soils in Inner Mongolia that may suggest moister
conditions at various stages during the Holocene. Jaekel (1995) reviews
evidence from various sites in Inner Mongolia (China) (at around 100 E
and 41-43 N) which suggest that conditions were moist enough for
permafrost to be present up until 7,000 years ago. They suggest on this
basis that steppe vegetation covered the region, instead of the
present-day desert and semi-desert vegetation. J. Olson (University of
Arizona, pers. comm. May 1995) has recently found pollen evidence of
moist steppic phases (so far undated) from the most arid parts of the
Mongolian Desert. He is of the opinion that these were probably lower
Holocene in age.

In a vegetation map presented for 6,000 years ago, but possibly
applicable to the whole period 8,000-5,000 years ago, Winkler & Wang
1993 p.245), most of the present-day grassland zone on the Tibetan
Plateau is depicted as being covered by a forest-grassland mosaic,
reflecting warmer and moister conditions. Likewise a forest-grassland
zone is shown as impinging from the north over much of the Mongolian
arid steppe zone. The result is much reduced desert/semi-desert zone in
central Asia.

More moist deciduous vegetation in SW China. In Sichuan Province,
SW China (around 30 N), Jarvis (1993) also finds pollen evidence for a
considerably stronger summer monsoon than at present between 9,100 and
7,800 14C years ago, with deciduous oaks (Quercus)
being more abundant than sclerophyllous evergreen ones in the
mid-altitude forests close to the edge of the Tibetan plateau.

Indo-China.Early Holocene humidity in Thailand. In the
Chi River basin, northeast Thailand, Tamura (1992) regards sedimentation
rates and sediment grades as indicating that a more humid than present
climate from early-to-mid Holocene time, up until around 3,500 years
ago. Likewise, the evidence from palaeo river channels in the northern
part of the central plain of Thailand (Yom River) is that water
discharges were three to four times greater than at present during the early to mid Holocene
(Bishop & Godley 1994). The present-natural vegetation of these
regions is rainforest, and given a still moister climate at 8,000 years
ago, the vegetation must presumably have been rainforest at that time.

S.E. Asia.Similar or moister vegetation conditions in
rainforest zone. The south east Asian tropical forest zone seems to
have had higher-than-present rainfall during the early Holocene (Flenley
pers. comm.), in at least some places close to the equator.
Barmawindjaja et al. (1993) note that in the northern Molucca Sea
(Indonesia) the indications are that essentially present-day vegetation
conditions have existed since around 14,000 years ago. Morley feels that
by 8,000 14C years ago the vegetation would have been
generally very similar to the present (Morley pers. comm. March '92).
For example, in mid-altitudes of central Sumatra, he finds pollen
evidence of essentially similar-to-present conditions by 8,600 years
ago.

India.Moister than present. There are various sources of
evidence (lake level, sea surface salinity, alluvial sedimentation)
showing peaks of humidity in northern and western India at around
11,000-10,000 14C years ago and 7,600-6,000 14C
years ago (e.g. Van Campo 1986, Petit-Maire et al. 1994), but
still much moister than present at around 8,000 years ago. However,
there do not appear to be any clear indications of the vegetation
conditions at that time. The most direct information relating to the
ecology appears to be from the assemblages of early-to-mid Holocene
animal bones from an archaeological site at Mohenjo-daro in the Sind
region at the western edge of the Thar Desert (Hyams 1976, p.69), in the
lower Indus valley. The Sind presently has a tamarisk and scrub
vegetation and a rainfall of around 150mm. The diverse Holocene
vertebrate fauna seems to indicate, in contrast, either humid park-land
or rainforest, with annual rainfall of at least 1200 mm. It is
unfortunate that Hyams only mentions this information in passing,
without giving details of the dating of this fauna, nor the literature
sources that he has used (except to say that the information is from
Piggott op. cit.).

From cores taken in the Indian Ocean, there is evidence of a
stronger-than-present monsoon flow over the Indian region (Van Campo
1986), which would be expected to have given moister conditions at 8,000
years ago, although no quantitative estimates of the rainfall change are
available.

By 8,500 years ago, the present-natural temperate deciduous forest had
returned to a site at 3000m, on the southern edge of the Himalayas in
Nepal. This forest was still in place at 5,000 years ago, and up until
the beginning of anthropogenic deforestation about 2,000 years ago
(Yasuda & Tabata 1988).

C3/C4 balance in upland (>2,000m) peats from the Nilgri Hills in
southern India record suggest herbaceous communities under conditions
with about the same moisture levels as today at 8,000 years ago,
although during the next few thousand years there was a strong arid
period (Sukumar et al. 1993).

5,000 14C years ago.

The available evidence points to significantly warmer and wetter
climates across the monsoon belt, with the summer monsoon rainfall
reaching further north than at present. Lake level evidence from widely scattered areas across Eurasia (western Siberia,
Mongolia, Yakutia and China) also suggests moister than present conditions at this time (Harrison et al. 1996).
In China, sea surface height may have reached its Holocene maximum at around 5,000-6,000 years ago, being
10m or more above its present level (Winkler & Wang 1993).

Similar-to-present rainforest distribution. Morley suggests that
by 5,000 years ago the vegetation across the tropical rainforest region
would have been generally very similar to the present - natural (Morley
pers. comm. March '92). In southern Borneo (Kalimantan), various studies
on the coastal peat swamps have shown peat deposition starting around
5,000-6,000 years ago (Morley 1981). At the upper lowland/montane
rainforest boundary in central Sumatra, Morley (1982) also suggests that
the first evidence of forest clearance occurs at about 4,000 years ago.

Warmer and moister conditions in China. Conditions across much of
China at 5,000 years ago seem to have been warmer than present, but
perhaps cooler than in the early Holocene (Winkler & Wang 1993). In
apparent contradiction to this, Sun & Chen (1991) note that
conditions throughout China seem to have remained similar at 5,000 years
ago to what they had been at 8,000 years ago, with warm temperate forest
extending hundreds of kilometres further north than at present. Sun
& Chen (1991) note that over much of China, palynological records
indicate temperatures 2-4°C warmer than at present (perhaps
5°C higher in the Tibetan Plateau), cooling after about 4,000-3,000
years ago. In the north-east of China ('Manchuria'), peat deposition
seems to have begun mainly around the mid-to-late Holocene, coincident
with a cooling of climate just after around 5,000 years ago. Lake
levels indicate conditions moister than present over most of China up
until 3,500 years ago (Fang 1991), and the same picture is indicated by
magnetic susceptibility of loess profiles (Li et al. 1995). The
presence of Neolithic agriculture in north-western regions of China
currently too arid for crop-growing is further testimony of the moister
climate which prevailed at around 5,000 years ago (Petit-Maire et
al. 1994). Agriculture was already present and expanding throughout
the south-east Asian region, but deforestation in southern China and in
the monsoon zones of Indo-China does not appear to have been significant
until after around 4,000 years ago (e.g. see Tallis 1990).

Moister in NW India. Likewise, in North-western India (Rajasthan)
there is lake level, anthropological and other evidence of
higher-than-present rainfall at around 5,000 years ago (Bryson &
Swain 1981). Alekseeva (1991) suggests on the basis of palaeochannels of
rivers that precipitation in winter exceeded the present by about
200-300mm at around 5,000-4,000 years ago. A figure of 500mm greater is
suggested by Singh et al. (1974), who on the basis of plant
fossils and the molluscan fauna reconstruct a savanna-grass steppe
environment for Rajasthan at that time, in contrast to the present
semi-desert. Hyams (1976, p.69) mentions vertebrate fossil evidence from
Sind, in the lower Indus Valley, indicating a rainforest or
rainforest-savanna environment during the mid-Holocene (though the
forest was presumably restricted to riverine borders). The original
source material that Hyam cites has not yet been obtainable. To the
north-west of this area, in southern Haryana, much moister-than-present
conditions are also indicated by palaeolake levels (Bhatia & Singh
1988).

Names of QEN participating experts (named in the text above) who have
made direct contributions to this work on South Asia:

Ice extent.Grosswald's view of large ice extent. There
has been a fair amount of controversy over the 18,000 y.a. ice
extent in northern Eurasia, and the differences in viewpoint are well
summarised by Dawson (1992). One perspective on ice extent is presented
by Grosswald (1980, 1995), and favoured by Denton & Hughes (1981),
suggesting relatively extensive glaciation, with a large ice lobe
extending eastwards across northern Siberia to about 110E. There would
have been large proglacial lakes along the southern edge of this ice in
western Siberia. See this unpublished manuscript for discussion of
the view that there may have been a single very large lake covering most
of the West Siberian Basin.

The larger ice extent was used by CLIMAP (1976) and is
widely presented in texts on the Quaternary. Grosswald (1995)
suggests that recent data from the ODP Leg 145 cruise support his view
of extensive glaciation across northern Siberia. The recent evidence
of the position of terminal moraines (Grosswald & Hugues 1995) and also ice-dammed lake sediments summarized
in the unpublished manuscript above, also seems to confirm a relatively
large ice extent, although not perhaps as large as Grosswald initial advocated.

Velichko et al.'s view of smaller ice extent. Another view
- which was used as a working hypothesis when the LGM here was being drawn up - is held by Velichko and
colleagues (e.g. Velichko et al. 1984). They suggest that LGM
glaciation was much less extensive, and this view is reflected in their
recent maps. The relatively conservative view seems to be more widely
accepted, but it is apparently put in doubt by the evidence of a greater LGM ice extent and
a very large ice-dammed lake (Goncharov 1989, and also see the link above) existed in the part of
western Siberia that Grosswald believes was glaciated. Ice sheet extent
in the map given here is taken from maps byVelichko &
Kurenkova (1990). Although in their scenario most of Siberia was free of
ice sheets at the LGM, the area would presumably have been permafrosted
if it was not ice covered.

It is also suggested by Grosswald (pers. comm., 1991) that various large
ice-caps also existed on mountains in the north-east of the Siberian
region (e.g. in the Putorana and Verkhoyansk Mountains). However,
Velichko et al. (1984) view these uplands as having only
scattered glaciation, in the form of mountain glaciers.

A mega-lake in west Siberia? Goncharov (1989) has found that the
whole west Siberian basin was covered by continuous lacustrine and
fluvio-lacustrine clays and silts. These molluscan and diatom-bearing
deposits are 14C dated as being close to the LGM. The lake,
dammed by a north-west Siberian ice sheet, may have flowed out into the
Caspian Sea through Kazakstan and the central Asian rivers. Goncharov
also suggests that the northern part of the area that Grosswald suggests
was glaciated was in fact covered by a marine transgression (due to
down-warping of the crust under the weight of the ice). This scenario is
shown - for example - as a variant in the recent set of maps produced by
Velichko's group in Moscow (Landscapes of Russia during the Late
Quaternary, A.A. Velichko et al. in press) and in the earlier map
of Velichko and Kurenkova (1990), although the most recent dating
evidence indicates that the true extent of the lake may have been
underestimated in these reconstructions.

Sea level. Shorelines at -150m bathymetric contour. Sea level was
probably 120 - 140 m lower, and would roughly correspond to the -150m
contour. The Black Sea was also somewhat lower; the Caspian Sea was
higher and more extensive. Their shorelines here are from Velichko &
Kurenkova (1990).

The region in general.Cold, arid conditions with sparse
vegetation.

There are few pollen records from anywhere within this vast
region that are radiocarbon dated from the LGM - a fact that is taken by
some (e.g. van Campo et al. 1993) as licence to reconstruct moist
tundra and boreal forest over the whole region. However, the case
against such vegetation existing on any broad scale is overwhelming when
one considers the circumstantial evidence surrounding the hiatus in
pollen data for the LGM. The level of understanding of the late-glacial
flora, fauna and geomorphology of this area is much greater than for
other areas in which direct LGM data are lacking, such as the Amazon
Basin.

The extensive literature on the Siberian region is mainly published in
Russian and thus inaccessible to most of us from the west. To some
extent, it has been expressed in published summary compilations by
Russian authors (e.g. in Frenzel et al. 1992) However, colleagues
from the Russian Academy of Sciences (in particular, A.A. Velichko, E.
Zelikson & C. Kreminetski) have carefully explained to me their
understanding of the literature concerning northern Eurasia during the
late glacial and LGM. This distillate of the evidence is based mainly on
conversations with them and other Russian Quaternary experts (named
within the text), against the background of summary maps such as those
published by Velichko & Kurenkova (1990) and in Frenzel et
al. (1992). Grichuk (1992) has published a map that seems at odds
with those of the others published for this region; large areas of
apparent 'forest' cover are shown across southern Siberia and in the
Caucuses. However, as Zelikson (pers. comm, 1992) has explained to me,
Grichuk's map is not in fact intended to deal with vegetation as we
would define it here, but instead biogeographic 'source' areas which
contained at least some populations (often very localised) of the
species of each particular biome.

The current consensus amongst Russian Quaternarists appears to be that
conditions almost everywhere across northern Eurasia were much colder
and drier than at present, with a virtual absence of woody vegetation
and only a sparse herbaceous ground cover, if any. The region has been
worked on thoroughly enough to show that conditions became progressively
colder and more arid after about 26,000 14C years ago, after
which sedimentary deposition and fossil preservation seem to have
largely stopped. Radiocarbon dated pollen records do not start appearing
until after 15,000 14C years ago in the north Eurasian
region, and even they show a dry, sparse vegetation in which the
open-ground coloniser Artemisia is an important component. The
lack of any surviving peat, pollen or other fossil deposits may in
itself be taken to indicate the extremely cold and arid nature of the
LGM climate. If there was much moisture around at that time, one would
expect at least some pockets of stream deposition of plant fossils to
have survived - yet it seems that there are none. C. Kreminetski (pers.
comm., May 1994) has compiled data on the records of fossil woody
material or other plant macrofossils across northern Siberia, and finds
that although there are large numbers of radiocarbon-dated records from
the period before about 25,000 years ago and after about 15,000 years
ago, records become progressively rarer and then are absent completely
for several thousand years in the period that includes the LGM. Thus for
example, woody fossils in the Ineisei Valley (central Siberia) are not
found after 24,000 14C years ago (Drozdov et al.
1995), with a gap in occurrence until several thousand years after the
LGM. Kreminetski also obtains a similar picture from the northern
Siberian records of fossil mammoths and other mammals, of which none
have been found for the LGM period.

Geomorphologic indicators from across northern Siberia (north of about
57 deg.) include widespread ventifacts (wind-sculpted desert pebbles)
and deflation pavements, indicating dry, very sparsely vegetated and
windy conditions (Spasskaya 1992). These features are thought to have
been formed during glacial periods, and the most recent layers of these
are used as a stratigraphic marker of the LGM (Kolpakov 1995). Where
loess deposition was occurring during the last glacial, the lack of soil
development within this loess is interpreted as a further indication of
the low biological activity of the northern Eurasian region during the
LGM period (Spasskaya 1992). Pollen records that may represent the LGM
period itself have been taken from within the loess, but there is too
little organic matter for reliable dating. They show a similar type of
dry, very sparse vegetation dominated by Artemisia.

After the resumption of fossil preservation at around 15,000
14C years ago, an increasing abundance of fossil sites and of
woody species indicates progressively warmer and moister conditions
towards the Holocene (C. Kreminetski pers. comm. May 1994).

As an additional source of opinion, A. Andreev (pers. comm. Inst.
Geography, Academy of Sciences, Moscow. April 1993) is adamant that
conditions all across Siberia at the LGM must have been very dry and
cold, without moist tundra or boreal forest. As further evidence he
cites the situation in western Siberia during the Younger Dryas when the
first dated cores are obtained, which does not seem to have been as cold
and dry as the preceding LGM, but which had a periglacial steppe-tundra
with the only arboreal vegetation being an open parkland which was
confined locally to the floodplains of river valleys. The colder LGM
would thus presumably have had even less of a woody component than the
Younger Dryas. In particular as a compilation of the evidence and
vegetation distributions for the LGM and early Holocene, he cites
another more recent monograph by Velichko (1993).

West, Central and Northern Siberia. The general picture across
this vast area - justified above - is of treeless, arid and extremely
cold landscapes at the LGM. The only indications from pollen in loess
are of a dry flora, of which Artemisia is a major component.
According to the predominant opinion amongst Russian palaeoecologists,
most of Siberia was covered with a virtually tree-less 'steppe-tundra'
or 'periglacial steppe'; a dry, open vegetation incorporating elements
of present-day steppe and tundra environments. Towards the north, and at
higher altitudes, this would have given way to polar rock desert and
ice.

Far eastern Siberia. Steppe tundra with a woody shrub
component in the extreme east. Recently obtained pollen records from
the Kolnya River region, west of Kamchatka, (Lozhkin et al. 1993)
span the LGM. The pollen spectra show drier and colder conditions than
at present, with Artemisia dominant but also Pinus,
Betula and Alnus (probably in their shrub forms, as they
normally occur at present in this region) collectively an important
component in the pollen record, probably as a shrubby mosaic in moister
places, with Artemisia most common in the drier microsites. These
far eastern sites appear to differ from the steppe-tundra in other
localities further west and north, in the relative abundance of woody
species and in the fact that Gramineae and other herb species do not
seem to have been abundant (Lozhkin et al. 1993). This area would appear to have been subject to influxes
of moist air from the north-west Pacific. The localities
discussed by Lozhkin et al. are in the upper valleys of
northward-draining rivers, but quite possibly a similar vegetation might
have existed across the broad lowland shelf area exposed to the south.
At higher altitudes and latitudes, in the mountain ranges that cover
most of the Russian Far East, the vegetation would presumably have been
more sparse than this, consisting mainly of polar desert due to low
temperatures and aridity.

Southern Siberia. Dry, generally treeless conditions in
southern Siberia. A belt of boreal forest extending across southern
Siberia at about the latitude of Baikal has been suggested by Grichuk
(e.g. Grichuk 1992). This view has also been taken up in other
reconstructions, such as those of Crowley (1994) and van Campo et
al. (1993). Whilst it appears likely that the hills and mountains of
southern Siberia were in some sense a refugium for the tree species that
constitute the present boreal forest (Frenzel 1992, Kreminetski pers.
comm.), there is no direct evidence of their occurrence there at the
LGM. The only pollen diagrams for this region are published in Russian,
one in the lower-to-mid altitudes of the mountains to the east and
another to the west of Baikal (Kreminetski, pers. comm. May 1994). These
pollen diagrams indicate a dry, sparse vegetation dominated by
Artemisia both before and after the LGM, but with a hiatus during
the LGM period. Tree pollen is completely absent for several thousand
years before and after the LGM. If trees were present, they must have
been confined to very isolated pockets.

Animal fossils of approximately LGM age occur scattered across this
south Siberian belt (approximately 50-57N, 120E to 40W) (Baryshnikov
& Markova 1992). Instead of indicating a boreal forest or woodland
environment, the species which occur are typical of the "mammoth
tundra-steppe" assemblage (including Saiga, Mammuthus and
Equus) which occur in the treeless LGM landscapes further west,
for which better pollen evidence is available. This would tend to
indicate an open, dry and sparsely vegetated environment all across this
belt. The fossil record of smaller mammals in the Baikal area (Alexeeva
1995) for the late Quaternary indicates phases in which central Asian
desert and steppe mammal species were present in what is now a forested
and wooded region. However, the chronology is not exact enough to show
whether these in fact corresponded to glacial phases.

At Lake Baikal, the occurrence of drier-than-present conditions is also
suggested by an increased aeolian sediment input at the time
corresponding to the Last Glacial Maximum, dated according to a
correlation with oceanic oxygen isotope records (Peck et al.
1994). Although increased wind speeds may have been a factor, Peck et
al. are of the opinion that there was also a drier climate. Further
indications of a dry, very open vegetation conditions and a windy
climate in the south Siberian belt is the widespread occurrence of
ventifacts (wind-eroded pebbles) of last glacial age, in areas both west
and east of Lake Baikal (Spasskaya 1992). Further west at the same
latitude, also within the belt assigned to boreal forest by Grichuk and
others, deflation hollows alternate with loess, again indicating a
predominantly sparse vegetation in a dry, windy climate (Spasskaya
1992). Velichko & Spasskaya (1991) point out the scattered presence
of ephemeral internally-draining lakes (alternating with deflation
episodes) between about 52 and 54N.

In a broad belt extending across Siberia between 52 and 60N, Velichko
& Spasskaya (1991) map large areas of wind-blown sands, and the
predominance of desert conditions at the LGM. Sand dunes appear to have
been active in what are presently the south-west Siberian steppe
regions, in the valleys of the Tobol, Irstysh and Ob Rivers (Volkov
& Zykina 1984). These sand ridge dunes were deposited on top of
alluvial terraces dating from about 20,000 years ago, and are older than
about 15,000 years ago when the first dated soils formed on top of them.

Central Asia.Expanded central Asian desert. Desert in
central Asia seems to have extended further northward and eastward than
at present, with the aridity within the core of that zone being more
severe than at present. In a sense, it seems to have extended northwards
to cover much of southern Siberia (see above), and also southwards across the
Iranian Plateau (see above). Loess deposition appears
to have occurred widely across east-central Asia during glacial
époques (though this correlation poorly constrained by dating),
implying some vegetation cover to stabilise the loess, but there was
insufficient biological activity for soil development at such times
(Dodonov 1988), in contrast with interglacial periods.

Lake levels of
the Aral Sea and Caspian Sea seem to have been higher at the LGM than in
the modern-day world (Velichko & Spasskaya 1991) suggesting greater
available moisture in the western Asian desert area. However, it is difficult
to understand where the extra moisture came from, unless periodic storms with
rapid runoff (leaving litle opportunity for vegetation to
benefit from it) were the source. The Aral Sea is currently fed from the western edge of the Himalayan Plateau, so its higher level at around the LGM
could reflect greater winter monsoon
rainfall in these mountain areas, combined with lower
evaporation rates in the cooler lowland desert. However, Kashmir - a present source area for the Aral Sea - is now generally thought to have been substantially
drier at the LGM. The Iranian Plateau (which shows evidence of
drier conditions during the Last Glacial) seems unlikely to have contributed significant moisture to the Caspain. Also, there appear
to have been very large areas of wind-blown sand sheets active in the
lowlands of the south-west Asian desert (Velichko & Spasskaya 1991),
implying much more arid and sparsely vegetated conditions than at
present. Many sources of evidence also suggest semi-arid conditions
across the Ukrainian and west Siberian Plains to the north.

The view that there was greater glacial-age aridity all across Central Asia is discussed by
Velichko and Kurenkova (1990) and also in the chapter on Central Asia in
the same volume (Soffer and Gamble 1990). Lake-level and pollen data
from north-west China adds to the general picture of greater aridity
across the central Asian desert belt at the LGM (Sun pers. comm. 1990);
(see the section on southern Asia, above). There is a notable lack of
any archaeological evidence of human habitation from the plains area
between the Caspian and Aral Seas and Lake Balkhash, despite the fact
that dated sites occur a couple of thousand years before and after the
LGM period (Madeskya 1990). This too may reinforce the general
impression of greater aridity in the central Asia area. However, in many
other fairly arid areas (e.g. the Zagros mountains) human habitation
seems to have continued right through the LGM.

8,000 14C years ago (early Holocene)

Siberian peatland areas. Extensive peat initiation. From
large numbers of dated columns of peat across the Siberian region, it
appears that peat initiation in most areas began around 9,000 - 8,000
years ago (C. Kreminetski, May 1994). Likewise, Tallis (1990), in a
diagram on page 348 (collated from a range of primary sources), suggests
peat build-up initiating around 9,000 - 10,000 years ago, though without
any quantitative indications of how extensive this peat initiation would
have been by 8,000 years ago.

Siberian vegetation in general. Greater northern forest extent
in Siberia. Forest had reached the arctic coasts in the north by
9000 14C years ago and is here shown extending somewhat
further northwards than at present, onto the continental shelf in the
north still exposed by the slightly lower sea level. There was a general
northwards shift of high-latitude vegetation belts relative to the
present, and an expansion of mesic vegetation out into the central Asian
desert zone. This follows maps compiled by Velichko (pers. comm.),
adding to earlier maps by Khotinsky (1984) which are based on large
numbers of pollen and plant macrofossil sites. In eastern Siberia,
various plant fossil sites suggest that boreal scrub was present over
most of the eastern peninsula (due to warmer and drier conditions?) in
an area now occupied by open boreal forest (Tallis 1990).

5,000 14C years ago

Although there were some differences in treeline position, conditions
were probably similar to the present. A moister central Asian desert
belt seems still to have existed, by extrapolation from moister
conditions elsewhere.

Names of QEN participating experts (named in the text above) who have
made direct contributions to this work on Northern Asia: